With the quick development of science and technology, the electronic device can be given more functionality to enhance the cost performance ratio of the electronic device. The electronic device having multi-function usually need to be configured more electronic components inside thereof. These electronic components increase not only the circuit density of the electronic device, but also the operating temperature of the electronic device. In order to avoid that the electronic device is overheating during the operation, the electronic device will be usually provided with a fan inside thereof. The electronic device in operating can be dissipated heat by the rotation of the fan. The operation of the fan is controlled by a fan chip so that the fan in operation is able to reach the required rotational speed.
The fan chip usually receives a pulse control signal from an external control unit via an input pin to control the related operations of fan according to the indication of the external pulse control signal. Besides, the fan chip is generally configured on a circuit board, the signal generated by the external control unit must be sent to the fan chip via these circuit wiring and electronic components on the circuit board. These circuit wiring and electronic components will cause a delay of signal transmission between the external control unit and the fan chip. Afterwards, if the delay of signal transmission between the external control unit and the fan chip is not detected and processed, which may make errors occurred in the controlling for the fan, and therefore affect the normal operation of other circuits.